This paper explores sustainable energy systems in ecovillages based on the concept of the Zero Energy Building. The cases discussed in this paper include BedZED in the United Kingdom and Masdar City in the Middle East. These two communities contain features characterized by the sustainable principles of the ecovillage concept by using renewable energy and reclaimed materials to reach a low/zero energy system in buildings. The creation of more ecovillages and the growth of current ecovillages play an important role in positively solving environmental and social problems. The low energy buildings in the ecovillages also act as a model for communities wishing to implement sustainable development.

To discuss the relationship between the periodicity noise and the aerodynamic noise source of a wind turbine, the characteristics of the actual wind turbine were measured by a wind tunnel; moreover, the flow around the impeller immersed in the uniform flow was solved by numerical simulation. In the observed wind turbine, when the mainstream velocity was 7.4 m/s or more, the power coefficient reached maximum at tip speed ratio 8. When the mainstream velocity increased in the driving condition of the maximum power point, the aerodynamic noise increased due to the periodicity noise in the vicinity of 1000 Hz and the broadband noise in the high-frequency domain. The noise sources were concentrated at the leading edge and trailing edge on the suction surface side. We experimentally indicated that the pressure fluctuation of the leading edge was the source of the periodicity noise.

The sustainable land management (SLM) project is seeking to engage with public institutions to explore the possibility of using the energy-switch principle presented by the carbon market to reduce emissions from inefficient use of biomass energy and discharge of human waste into the environment. Such a switch will be a triple-win situation that improves the natural environment, reduces deforestation, and provides avenues for revenue generation. As such, it commissioned a study of the pattern of energy consumption in the institutions and the type of cooking stoves they employ. Results show that firewood (51%) is the most widely used fuel because of availability, affordability, and reliability. The study also found that 56% of the institutions use energy-saving stoves, which is an opportunity that the project can seize to encourage use of alternatives sources of energy as opposed to biomass. In addition, 88% of the institutions expressed willingness to switch to biogas for cooking. This is yet another opportunity for scaling up the dissemination of renewable sources of energy in the region. Better adoption and wider use of renewable energy sources will take place when innovative financing mechanisms are devised to cover the high upfront cost of installing renewable energy systems. This has been one of the main barriers to scaling up the use of renewable in the region.

United Republic of Tanzania Population and Housing Census (2013) Population Distribution by Administrative Areas. National Bureau of Statistics, Ministry of Finance, Dar es Salaam, and Office of Chief Government Statistician, President’s Office, Finance, Economy and Development Planning, Zanzibar, 244 p.

International Energy Agency and World Health Organization (2010) Energy Poverty: How to Make Modern Energy Access Universal? Special Early Excerpt of the World Energy Outlook 2010 for the 2010 UN MDG Review Summit.

The increasing penetration of wind power presents many technical challenges to power system operations. An important challenge is the need of voltage control to maintain the terminal voltage of a wind plant to make it a PV bus like conventional generators with excitation control. In the previous work for controlling wind plant, especially the Doubly Fed Induction Generator (DFIG) system, the proportional-integral (PI) controllers are popularly applied. These approaches usually need to tune the PI controllers to obtain control gains as a tradeoff or compromise among various operating conditions. In this paper, a new voltage control approach based on a different philosophy is presented. In the proposed approach, the PI control gains for the DFIG system are dynamically adjusted based on the dynamic, continuous sensitivity which essentially indicates the dynamic relationship between the change of control gains and the desired output voltage. Hence, this control approach does not require any good estimation of fixed control gains because it has the self-learning mechanism via the dynamic sensitivity. This also gives the plug-and-play feature of DFIG controllers to make it promising in utility practices. Simulation results verify that the proposed approach performs as expected under various operating conditions.

This paper deals with a dynamic analysis of an optimal technique used for direct electrical energy storage, where a concept of charge transfer between different electric storage units is used. This analysis is developed to seek for efficient and real time conditions to maintain optimal behavior for charge recovery from intermittent power sources in the field of renewable energies like solar and wind. The proposed analysis leads to elaborating a set of interesting states and conditions that allows the user to choose effective configuration parameters that lead to an optimal or near optimal charge transfer device. The proposed device is designed to ensure an optimal transfer of electric charges. It must be self-configured to retrieve and transfer the maximum energy from the sources to the storage units (Super-capacitors, batteries…). Some interesting results, by simulating the proposed device, are presented to show how this optimization problem can be viewed as a combinatorial one, where the optimization algorithm is asked to find the suitable switching combination to configure the device to be closest to the optimal charge recovery.

This paper aims at presenting different pumped-storage solutions for improving the energy efficiency and economic sustainability of water systems. The assessment of pumped-storage solutions, either using fresh water or sea-water, is seen as a viable option to solve problems of energy production, as well as in the integration of intermittent renewable energies, providing system flexibility due to energy loads’ fluctuation, as long as the storage of energy from intermittent sources. Pumped-storage is one of the best and most efficient options in terms of renewable resources as an integrated solution allowing the improvement of the energy system elasticity and the global system efficiency. Two real case studies are presented: a fresh water system installed in a river dams—the Alqueva system, in Portugal—and a sea-water system in an arid region of the Cape Verde Islands in Africa. These cases demonstrate the benefits associated to pumped-storage solutions, depending on the storage volume capacity, operational rules and energy tariffs.

The problem of profile matching in electronic social networks asks to find those offering profiles of actors in the network fitting best to a given search profile. In this article this problem is mathematically formulated as an optimization problem. For this purpose the underlying search space and the objective function are defined precisely. In particular, data structures of search and offering profiles are proposed, as well as a function measuring the matching of the attributes of a search profile with the corresponding attributes of an offering profile. This objective function, given in Equation (29), is composed of the partial matching degrees for numerical attributes, discrete non-numerical attributes, and fields of interests, respectively. For the matching degree of numerical profile attributes a fuzzy value approach is presented, see Equation (22), whereas for the matching degree of fields of interest a new measure function is introduced in Equation (26). The resulting algorithm is illustrated by a concrete example. It not only is applicable to electronic social networks but also could be adapted for resource discovery in grid computation or in matchmaking energy demand and supply in electrical power systems and smart grids, especially to efficiently integrate renewable energy resources.